Modern automobiles, having front wheel drive, include a sealed wheel bearing. It is difficult, or impossible, to gain access to the wheel bearing for a visual inspection of the wheel bearing. Therefore, eccentricity of the wheel bearing can remain undetected until causing damage to a tire and affect overall smoothness of a ride of the automobile.
Repairs, therefore, encompass a complete replacement of a wheel bearing assembly, at a substantial expense. It is also possible to later learn that the wheel bearing was not defective and the same problems remain.
Prior practices to detect the presence of a defective wheel bearing include the use of a stethoscope. A stethoscope is used in an attempt to hear a vibration produced by a defective wheel bearing. However, rotation of the wheel by a drive shaft can adversely affect the sounds heard by the stethoscope. The drive shaft noises can be attributed to a defective wheel bearing and result in expensive replacement of a wheel bearing when the wheel bearing was not in need of replacement.